<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>V3</title>   
  </head>
  <body>
    <div id="app">
      <input @keyup.enter="ku" />  
        <button v-on:click="f2( 1,2,3  ,$event )"> button2</button>
        <button v-on:click="f1"> {{ btntext }}</button>

        <button @:click="this.show =!this.show"> count  ++  </button>

        {{ count }}
      
        <div v-show="show">
          show 
        </div>
        <div v-if="show">
          if 
        </div>
      
         {{ message  }}         
    </div>   
  </body>
</html>
<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script>
   
  const { createApp } = Vue;
  createApp({    
    data() {
      return {       
        message: "Hello Vue!",     
        show: true,   
        count :0,
        btntext:"aaa"
      };
    },  
    methods: {
      ku(event ){
        console.log(event.key);
      },
      f2(x,y,z,e ){
        console.log(e );
       
      },
      f1(e){
        console.log(e.target);
        this.btntext ="bbbb"
      }
      // f1(event ){
      //   console.log(event);
      // }
    }, 
  }).mount("#app");
</script>
